Add test for editing patch Cargo.toml files (#3063)

This tests that the repository rules are properly invalidated when
patched Cargo.toml files are edited.

.bazelci/presubmit.yml

@@ -539,17 +539,13 @@ tasks:
     platform: ubuntu2004
     working_directory: examples/crate_universe_local_path
     run_targets:
-      - "//:vendor_lazy_static_out_of_tree"
-    test_targets:
-      - "//..."
+      - "//:vendor_edit_test_out_of_tree"
   crate_universe_local_path_in_tree:
     name: Crate Universe Local Path In Tree
     platform: ubuntu2004
     working_directory: examples/crate_universe_local_path
     run_targets:
-      - "//:vendor_lazy_static_in_tree"
-    test_targets:
-      - "//..."
+      - "//:vendor_edit_test_in_tree"
 # See https://github.com/bazelbuild/rules_rust/issues/2186 about re-enabling these.
 #  crate_universe_examples_windows:
 #    name: Crate Universe Examples

examples/crate_universe_local_path/BUILD.bazel

@@ -12,3 +12,19 @@ sh_binary(
         "vendored_lazy_static",
     ],
 )
+
+sh_binary(
+    name = "vendor_edit_test_out_of_tree",
+    srcs = ["vendor_edit_test.sh"],
+    args = [
+        "//:vendor_lazy_static_out_of_tree",
+    ],
+)
+
+sh_binary(
+    name = "vendor_edit_test_in_tree",
+    srcs = ["vendor_edit_test.sh"],
+    args = [
+        "//:vendor_lazy_static_in_tree",
+    ],
+)

examples/crate_universe_local_path/vendor_edit_test.sh

@@ -0,0 +1,55 @@
+#!/bin/bash
+
+set -euo pipefail
+set -x
+
+cd "${BUILD_WORKSPACE_DIRECTORY}"
+
+if [[ "$#" -ne 1 ]]; then
+  echo >&2 "Usage: $0 //:vendor_target"
+  exit 1
+fi
+vendor_target="$1"
+
+echo >&2 "Patching lazy_static dependency"
+
+vendored_lazy_static_dir="$(bazel run "${vendor_target}" | awk '$0 ~ /Copied to/ {print $3}')"
+echo >&2 "Vendored lazy_static to ${vendored_lazy_static_dir}"
+
+echo >&2 "Running test which is expected to pass, now that patch is applied"
+bazel test ...
+
+echo >&2 "Changing the version of the vendored crate, so that the patch no longer applies"
+sed_i=(sed -i)
+if [[ "$(uname)" == "Darwin" ]]; then
+  sed_i=(sed -i '')
+fi
+"${sed_i[@]}" -e 's#^version = "1\.5\.0"$#version = "2.0.0"#' "${vendored_lazy_static_dir}/Cargo.toml"
+
+echo >&2 "Running build which is expected to fail, as the patch no longer applies"
+
+set +e
+output="$(bazel build ... 2>&1)"
+exit_code=$?
+set -e
+
+if [[ "$exit_code" -ne 1 ]]; then
+  echo >&2 "Expected build failure, but exit code was ${exit_code}. Output:"
+  echo >&2 "${output}"
+  exit 1
+fi
+
+if [[ "${output}" != *"cannot find value \`VENDORED_BY\` in crate \`lazy_static\`"* ]]; then
+  echo >&2 "Expected compile failure due to missing VENDORED_BY symbol because the patch stopped applying. Output:"
+  echo >&2 "${output}"
+  exit 1
+fi
+
+echo >&2 "Build failed as expected, making patch re-apply"
+
+"${sed_i[@]}" -e 's#^version = "2\.0\.0"$#version = "1.5.0"#' "${vendored_lazy_static_dir}/Cargo.toml"
+
+echo >&2 "Running test which is expected to pass, now that patch is re-applied"
+bazel test ...
+
+echo >&2 "Test passed as expected"